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QESM: The QUEST Earth System Model

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Title: QESM: The QUEST Earth System Model


1

QESM The QUEST Earth System Model _at_Reading
Manoj Joshi, Jonathan Gregory, Allan Spessa,
Annette Osprey _at_CEH Wallingford Eleanor Blyth,
Doug Clark _at_UEA Erik Buitenhuis, Corinne Le
Quéré _at_Leeds Ken Carslaw, Graham
Mann _at_Cambridge Luke Abraham, Olaf Morgenstern,
John Pyle _at_Lancaster Oliver Wild and many
others...
2
  • QESM the QUEST Earth System Model
  • An unprecedented attempt to simulate the
    direction and strength of a wide range of
    biogeochemical processes and feedbacks affecting
    the functioning of the Earth system under
    contemporary and likely future climate scenarios.
  • Coordinated and managed by the NCAS-Climate and
    the Walker Institute. Its development builds upon
    the efforts of several exisiting modelling
    consortia currently engaged in the development of
    the climatic and biogeochemical models
  • http//www.quest-esm.ac.uk/



3
Climate models have historically been comprised
of the following components atmospheric
dynamics/physics ocean dynamics/physics sea-ice la
nd surface processes

Atmospheric chemistry aerosols mostly offline
as climatologies
Atmospheric physics dynamics

Ocean biology
Land processes
Ocean and sea-ice
4
Earth system models are comprised of the
following components atmospheric
dynamics/physics ocean dynamics/physics sea-ice oc
ean biology atmospheric chemistry land surface
processes dynamic terrestrial vegetation

Atmospheric chemistry aerosols
Atmospheric physics dynamics

Ocean biology
Ocean biology
Dynamic vegetation
Land processes
Ocean and sea-ice
5
QUESM will be comprised of the following
components HadGEM3-A NEMO (Nucleus for European
Modelling of the Ocean) CICE (Community Ice
CodE) QPFT UKCA JULES (Joint UK Land Environment
Simulator) ED (Ecosystem Dynamics)

6
  • Planned and ongoing work on QESM
  • The QESM is being developed in parallel with the
    Met Office Hadley Centres HadGEM3 model (an
    updated version of HadGEM1/1a)
  • There is a close relationship in timetable and
    components
  • HadGEM3-A (the atmosphere component of HadGEM3)
    will be run at N96 or above QESM atmosphere is
    planned to run at N48
  • HadGEM3-AO will (probably) have an ocean
    resolution of 1, while QESM will run at 2
  • The coarser resolution enables greater
    flexibility, such as running with 60 atmospheric
    layers in the vertical, and running it on systems
    such as the QUEST cluster



7
  • QESM progress so far
  • Three major changes have been tested in the N48
    atmospheric model since the freezing of
    HadGEM2-OA in early 2007
  • a parameterisation of surface-atmosphere exchange
    at coastal points (this is still under
    development)
  • implementation of adaptive detrainment on shallow
    convection
  • changes to the convective cloud/precipitation
    scheme when the cloud depth is small (lt3 km)
    (also under development)



8
  • QESM progress so far
  • A parameterisation of surface-atmosphere exchange
    at coastal points (this is still under
    development)
  • This is an attempt to solve the problem of land
    drag dominating the momentum budget at coastal
    points, lowering windspeed, and lowering moisture
    exchange
  • The surface-lowest model layer windshear is
    tweaked upwards over the ocean fraction, and
    reduced over the land fraction
  • It's a bit ad-hoc, but it does dramatically
    improve moisture in the BL and rainfall over the
    Maritime continent (probably also by broadly
    representing sea breezes)
  • Its presence also fixes the AMOC drift in the N48
    model, which is now 17-18 Sv in the latest
    integration


9
  • QESM progress so far
  • A parameterisation of surface-atmosphere exchange
    at coastal points (this is still under
    development)


10
  • QESM progress so far
  • A parameterisation of surface-atmosphere exchange
    at coastal points (this is still under
    development)


Reduced these tendencies
11
  • QESM progress so far
  • implementation of adaptive detrainment on shallow
    convection
  • changes to the convective cloud/precipitation
    scheme when the cloud depth is small (lt3 km)
  • both of these improve the rainfall field,
    especially the monsoon


12
  • QESM progress so far
  • implementation of adaptive detrainment on shallow
    convection, changes to the convective
    cloud/precipitation scheme when the cloud depth
    is small atmos-only results


13
  • QESM progress so far
  • In coupled mode, there are still problems, but
    the N48 AO model with the latest fixes displays
    performance that is comparable (ish) with
    HiGEM/HadGEM, e.g. JJA rainfall


14
  • QESM progress so far
  • e.g. NINO3 timeseries


15
  • QESM progress so far
  • e.g. ENSO periodicity


16
  • QESM progress so far and future plans
  • Progress with the N48 model
  • viable! (remember this wasn't the case earlier
    with the N48 model's "P minus E" problems)
  • N48 HadGEM2-A is 4.5x as quick as N96 HadGEM2-A
  • There are still ongoing issues similar to
    HadGEM/HiGEM
  • Future work
  • We're soon moving from HadGEM2 to HadGEM3
  • a different ocean means different coupled
    problems, so there's not much point in more
    tweaking


17
  • QESM progress so far and future plans
  • Progress with the N48 model
  • viable! (remember this wasn't the case earlier
    with the N48 model's "P minus E" problems)
  • N48 HadGEM2-A is 4.5x as quick as N96 HadGEM2-A
  • There are still ongoing issues similar to
    HadGEM/HiGEM
  • Future work
  • We're soon moving from HadGEM2 to HadGEM3
  • a different ocean means different coupled
    problems, so there's not much point in more
    tweaking ...for the moment
  • Keeping in contact with the Met O's HadGEM3
    development


18
  • QESM progress so far and implications for HiGEM
  • Perhaps the HadGEM3 implementation of the coastal
    mod can be tested in HiGEM- might have an effect
    on the Maritime Continent and the SW
    Pacific/Andes region (c.f HadGEM1a/WAN)
  • Adaptive detrainment/entrainment has had
    beneficial effects on everything from the N48
    model to the global NWP model the river outflow
    scheme presently in HadGEM2 has had beneficial
    effects
  • The convective cloud changes would probably
    improve HiGEM performance
  • As for other coupled biases- sorry, not really my
    job anymore
  • but that doesn't mean I haven't got one or two
    ideas


19

Thank you for your attention
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